1. Field of the Disclosure
The present disclosure relates generally to cutting windows in casings and forming lateral wellbores from a main wellbore using a mud motor-driven cutting device.
2. Description of the Related Art
Many operations in wellbores for recovery of hydrocarbons (oil and gas) include milling a portion of a casing in the wellbore or forming a lateral wellbore from a main cased or open wellbore. Windows are milled or the side wells are formed from specified locations in the main wellbore. To perform such a cutting operation during a single trip, a downhole tool is conveyed in the wellbore that includes a whipstock connected to a cutting device. The cutting tool is operated by a fluid-driven motor, such as a progressive cavity motor. The motor is typically mechanically locked to prevent it from rotating the cutting tool as that will cause the whipstock to rotate. Once the whipstock has been oriented, an anchor attached below the whipstock is hydraulically set by flowing fluid through the locked motor and without breaking the lock on the motor. After the anchor and whipstock have been set, the cutting device is mechanically disengaged from the whipstock and the motor lock is hydraulically broken by rotating the motor. The cutting device is then lowered along the whipstock to perform a milling operation.
The disclosure herein provides apparatus and method for performing milling/cutting operations downhole without locking the motor or flowing fluid through the motor to set the anchor.